function ajax(method,url,data,success){
	var xhr=null;
	try{
		xhr=new XMLHttpRequest();
	}catch(e){
		xhr=new ActiveXObject('Microsoft.XMLHTTP');
	}
	
	if(method =='get' && data){
		url+='?'+data;
	}
	
	xhr.open(method,url,true);
	if(method == 'post'){
		xhr.send();
	}else{
		xhr.setRequestHeader('content-type','application/x-www-form-urlencoded');
		xhr.send();
	}	
	xhr.onreadystatechange=function(){
		if(xhr.readyState==4){
			if(xhr.status==200){
				success &success(xhr.responseText);
			}else{
				alert('出错了，Err：'+xhr.status);
			}
		}
	}
}						
		
